How about, “So long, cheapskate”? Or “No, thanks” whenever he asks you to do something.
It doesn’t matter who makes more money. You are a couple–you share everything else, and you should share the financial burden of your dates. If he were unemployed, it might be different, but he’s not. He can afford to pay sometimes. If he can’t, maybe you shouldn’t go out so much. Or maybe he should offer to make you dinner at home. Does he?
As for paying for everything in college–if that is even true–did you ask him to do that? I doubt it. I’m guessing he volunteered because he wanted to. Did he ever say, “I’ll pay now, but one day in the future you’ll have to pay for everything”? Of course he didn’t. So he can hardly collect on a debt now when you had no idea there would be a debt in the first place.
I’m sure you are grateful for him covering you in the past, and there’s nothing wrong with picking up the tab sometimes now that you are financially able. But he’s treating it like you owe him, and you don’t. Not every single bill. That’s ridiculous.
He’s being a lazy freeloader. Tell him your days of paying for everything are over. You can share the burden or stop going out.
Thanks for the question.